Ultrasound imaging system and ultrasound imaging method using the same

Abstract

An ultrasonic imaging system and an ultrasonic imaging method using the same include a channel unit, a correction unit, an imaging unit, and a reference information providing unit. The channel unit includes a plurality of channels for transmitting and receiving ultrasonic waves. The correction unit corrects distortion due to an ultrasonic barrier using the ultrasonic signal received by the channel unit. The imaging unit visualizes the ultrasonic signal as an ultrasonic image. The reference information providing unit provides the correction unit with reference information necessary for correction. In this case, the correction unit determines a sample interval using the reference information and corrects attenuation distortion and aberration distortion due to the ultrasonic barrier based on the signal in the sample interval. The imaging method controls the position of the ultrasonic probe to improve the signal-to-noise ratio of the target object and facilitate attenuation distortion and aberration distortion correction. The imaging method applies the time delay set obtained by the aberration correction process to the ultrasonic transmission channel signal to provide physical attenuation distortion and aberration distortion correction.

Description

Technical Field

[0001] The present invention relates to an ultrasonic imaging system and an ultrasonic imaging method using the same. More specifically, the present invention relates to an ultrasonic imaging system that images a distorted object beyond a barrier that scatters or refracts ultrasonic waves with high resolution, and an ultrasonic imaging method using the same.

Background Art

[0002] The technology of ultrasonic imaging diagnosis is widely used for diagnosing organs without ultrasonic barriers such as bone or gas, such as liver, breast, and thyroid ultrasounds.

[0003] On the other hand, organs surrounded by or adjacent to barriers that are difficult to transmit ultrasonic waves and cause disordered refraction and scattering of signals, such as the skull, ribs, respiratory organs, or gas in the digestive organs, such as the brain, heart, lungs, stomach, and intestines, are difficult to use ultrasonic imaging diagnosis.

[0004] Especially in the case of the brain protected by the skull, clear images can be obtained only through the gap of the skull called the great fontanelle in the neonatal period. In the case of adults, it is very difficult to obtain brain ultrasonic images, and only cerebral blood flow ultrasound is used limitedly.

[0005] Also, when obtaining ultrasonic images of the heart, ultrasonic waves are transmitted and received through the rib gap, and imaging diagnosis is performed with low resolution within a limited imaging range. In the case of the lungs, ultrasonic imaging diagnosis is impossible due to the ribs and internal gas. For digestive organs such as the stomach and intestines, ultrasonic imaging diagnosis is also impossible due to internal gas.

[0006] In such cases where ultrasonic imaging diagnosis is impossible, imaging diagnostic devices such as CT and MRI are used. However, such imaging diagnostic devices cannot be used in emergency sites such as general ambulances or emergency rooms due to low mobility (CT, MRI), radiation hazards (CT), contrast agent toxicity (CT, MRI), reservation waiting (MRI), etc., and are not suitable for use in emergency sites where quick response is required or critically ill patients who require continuous monitoring.

[0007] A related prior art document is Registered Patent No. 10-2146374 of the Republic of Korea. [Overview of the project] The problem to be solved

[0008] The object of the present invention is to provide an ultrasonic imaging system and an ultrasonic imaging method using the same, which corrects signals distorted by an ultrasonic barrier that scatters or refracts ultrasonic waves, thereby imaging distorted objects in high resolution.

[0009] Another object of the present invention is to provide an ultrasonic imaging system and an ultrasonic imaging method using the same, which can correct attenuation distortion caused by an ultrasonic barrier by equalizing the signal amplitude of the sample section estimated to be the target object signal.

[0010] Another object of the present invention is to provide an ultrasonic imaging system and an ultrasonic imaging method using the same, which can correct aberration distortion caused by an ultrasonic barrier by moving the ultrasonic signal extraction section channel by channel.

[0011] Furthermore, another object of the present invention is to provide an ultrasonic imaging system and an ultrasonic imaging method using the same, which can automatically move the position of the channel to a position with less scattering noise in order to correct scattering distortion. [Means for solving the problem]

[0012] The ultrasonic imaging system according to the present invention includes a channel unit, a correction unit, an imaging unit, and a reference information providing unit. The channel unit includes a plurality of channels for transmitting and receiving ultrasonic waves. The correction unit corrects distortion caused by an ultrasonic barrier using the ultrasonic signal received by the channel unit. The imaging unit visualizes the ultrasonic signal as an ultrasonic image. The reference information providing unit provides the correction unit with reference information necessary for correction. In this case, the correction unit determines a sample interval using the reference information and corrects attenuation distortion and aberration distortion caused by the ultrasonic barrier based on the signal in the sample interval.

[0013] The correction unit uses the reference information to determine a sample section in which ultrasonic signals reflected from the target object can be received. When correcting attenuation distortion, the unit separates the signal from the sample section from the ultrasonic signal received by the channel unit, equalizes the amplitude of the separated ultrasonic signals, and corrects the attenuation distortion caused by the ultrasonic barrier. When correcting aberration distortion, the unit applies a sampling time delay to each channel, extracts the signal to be visualized, and corrects the aberration distortion caused by the ultrasonic barrier.

[0014] The correction unit determines an initial sampling time delay set in which it is predicted that an ultrasonic signal reflected from the target object has been received, sets multiple sampling time delay sets within a certain interval range from the determined initial sampling time delay set, selects a sampling time delay set that can generate an image with a preset optimal image quality as the optimized sampling time delay set, and extracts the signal to be visualized using the selected optimized sampling time delay set.

[0015] The correction unit determines the initial sampling time delay set so that the signal with the strongest signal intensity is extracted from the ultrasonic signal received by the channel unit.

[0016] The aforementioned reference information includes one or more of the following: ultrasonic velocity in the ultrasonic barrier, ultrasonic velocity in the section outside the ultrasonic barrier, thickness of the ultrasonic barrier, distance to the object, size of the object, and distance between objects.

[0017] The aforementioned reference information includes a reference ultrasonic signal to a reference object whose shape is already known and which has been photographed together with the target object, or a reference image which is a video of the aforementioned reference ultrasonic signal, and the aforementioned reference ultrasonic signal or reference image is acquired without an ultrasonic barrier.

[0018] The correction unit determines the sample interval by considering the time difference between the section in the received ultrasonic signal in which a signal indicating the reference object is received and the section in the reference ultrasonic signal in which a signal indicating the reference object is received, as well as the distance difference between the reference object and the target object.

[0019] The correction unit selects the optimized sampling time delay set from among a plurality of sampling time delay sets based on image quality, and the optimized sampling time delay set based on image quality is a sampling time delay set that can either maximize the brightness of the target object, minimize the size of the focal point, or generate an ultrasonic image with a shape that is most similar to the shape of a known target object.

[0020] The correction unit selects, from among a plurality of sampling time delay sets, the sampling time delay set that minimizes the standard deviation or variance of intensity between the ultrasonic image obtained by the corrected ultrasonic signal and the corresponding reference image pixels, as the optimized sampling time delay set.

[0021] Another embodiment of the present invention provides an ultrasonic imaging method comprising the steps of: transmitting an ultrasonic signal toward an ultrasonic barrier; receiving an ultrasonic signal distorted by the ultrasonic barrier; providing reference information necessary for correction; determining a sample section in which an ultrasonic signal reflected from an object can be received using the reference information; correcting attenuation distortion due to the ultrasonic barrier based on the signal in the sample section; correcting aberration distortion due to the ultrasonic barrier based on the signal in the sample section; and imaging the corrected ultrasonic signal with an ultrasonic image.

[0022] In the step of correcting the attenuation distortion, the signal of the sample section is separated from the received ultrasonic signal, and the amplitude of the separated ultrasonic signal is made uniform to correct the attenuation distortion due to the ultrasonic barrier. In the step of correcting the aberration distortion, a sampling time delay is applied to each channel to extract the signal to be visualized, and the aberration distortion due to the ultrasonic barrier is corrected.

[0023] The steps for correcting the aberration distortion include: determining an initial sampling time delay set in which it is predicted that an ultrasonic signal reflected from the target object has been received; setting a plurality of sampling time delay sets within a certain interval range from the initial sampling time delay set; selecting an optimized sampling time delay set that can generate an image with a preset optimal image quality; and extracting the signal to be imaged using the selected optimized sampling time delay set.

[0024] The step of determining the initial sampling time delay set involves determining the initial sampling time delay set such that the signal with the strongest signal intensity is extracted.

[0025] The aforementioned reference information includes one or more of the following: ultrasonic velocity at the ultrasonic barrier, ultrasonic velocity in the section outside the ultrasonic barrier, thickness of the ultrasonic barrier, distance to the object, size of the object, and distance between objects.

[0026] The step of providing the aforementioned reference information involves detecting a reference object whose shape is already known and which has been photographed together with the object, and providing a reference ultrasonic signal for the object acquired without an ultrasonic barrier, or a reference image of the reference ultrasonic signal, as reference material.

[0027] A sampling time delay set is selected as the optimized sampling time delay set, which minimizes the standard deviation or variance of the intensity between the ultrasonic image obtained by the corrected ultrasonic signal and the corresponding reference image pixels.

[0028] The optimized sampling time delay set is a sampling time delay set among the sampling time delay sets that can maximize the brightness of the object, minimize the size of the focus, or generate an ultrasonic image with a shape most similar to the known shape of the object.

[0029] An ultrasonic imaging method according to another aspect of the present invention includes transmitting an ultrasonic signal toward an ultrasonic barrier, receiving the ultrasonic signal distorted by the ultrasonic barrier, calculating a signal-to-noise ratio (SNR) of an object, changing a probe position to reduce the signal-to-noise ratio, correcting attenuation or aberration distortion caused by the ultrasonic barrier based on a signal in a sample section, and converting the corrected ultrasonic signal into an ultrasonic image.

[0030] Also, an ultrasonic imaging method according to another aspect of the present invention includes transmitting an ultrasonic signal toward an ultrasonic barrier, receiving the ultrasonic signal distorted by the ultrasonic barrier, correcting attenuation or aberration distortion caused by the ultrasonic barrier based on a signal in a sample section, calculating a resolution condition of an object, applying an optimal time delay set for aberration correction to a signal transmission channel to irradiate newly beamformed ultrasonic waves, and converting the corrected ultrasonic signal into an ultrasonic image.

[0031] The ultrasonic imaging method further includes calculating a signal-to-noise ratio of the object and changing a probe position to reduce the signal-to-noise ratio.

Effect of the Invention

[0032] According to the present invention, in a signal distorted by an ultrasonic barrier, the position of the channel portion is moved so that scattering distortion is included as little as possible, the amplitude of the signal in which attenuation distortion occurs is scaled, and an appropriate sampling time delay is applied to each channel of the signal in which aberration distortion occurs, thereby enabling high-resolution imaging of an object beyond an ultrasonic barrier.

[0033] Furthermore, the present invention can be widely used not only in medical ultrasound imaging diagnostic devices that transmit and receive ultrasound waves into barrier tissues with non-uniform physical properties and shapes, such as bone tissue, soft tissue, and gas, which induce aberrations, attenuations, and scattering distortions of ultrasound, but also in various non-destructive testing industrial fields that use ultrasound to visualize barriers (composite materials, thermal insulation materials, rust and sludge in pipes, etc.) that induce aberrations, attenuations, and scattering distortions of ultrasound, including solids (metals, ceramics, plastics, etc.) or fluid substances of multiple compositions. [Brief explanation of the drawing]

[0034] [Figure 1] This is a block diagram of an ultrasonic imaging system according to one embodiment of the present invention. [Figure 2] This is a block diagram of an ultrasonic imaging system according to another embodiment of the present invention. [Figure 3] Figure 2 shows an example of a position adjustment method using the position adjustment unit. [Figure 4] This is a sequence diagram of an ultrasonic imaging method using an ultrasonic imaging system according to one embodiment of the present invention. [Figure 5] Figure 4 is a sequence diagram showing the damping distortion correction steps. [Figure 6] Figure 4 is a sequence diagram showing the aberration and distortion correction steps. [Figure 7] This is a sequence diagram of an ultrasonic imaging method using an ultrasonic imaging system according to another embodiment of the present invention. [Figure 8] Figures 8a and 8b show the ultrasound signal and ultrasound image of a vascular model tube acquired without an ultrasound barrier, respectively. [Figure 9]Figures 9a and 9b show the ultrasound signal and ultrasound image of the vascular model tubes in Figures 8a and 8b, respectively, acquired with an ultrasound barrier. [Figure 10] Figures 10a and 10b show the ultrasonic signals and images obtained by correcting the ultrasonic signals from Figures 9a and 9b using the ultrasonic imaging system shown in Figure 1 or Figure 2. [Figure 11] Figure 11 is a sequence diagram of an ultrasonic imaging method using an ultrasonic imaging system according to yet another embodiment of the present invention. [Figure 12] Figure 12 is a sequence diagram of an ultrasonic imaging method using an ultrasonic imaging system according to yet another embodiment of the present invention. [Explanation of Symbols]

[0035] 10: Channel section 20: Correction section

[0036] 30: Video Production Department 40: Reference Information Provision Department

[0037] 50: Position adjustment section 100, 100': Specific details for carrying out the ultrasonic imaging system invention

[0038] The ultrasonic imaging system and method according to the present invention will be described in detail below with reference to the attached drawings.

[0039] In the following description, only the parts necessary for understanding the ultrasonic imaging system and method according to the embodiments of the present invention will be explained, and descriptions of other parts may be omitted so as not to obscure the essence of the present invention.

[0040] Furthermore, the terms and words used in this specification and claims, as described below, should not be interpreted in a way that is limited to their ordinary or dictionary meanings, but rather should be interpreted as meanings and concepts that are consistent with the technical idea of ​​the present invention, so as to best represent the present invention.

[0041] Throughout the specification, when a part "includes" a component, this means, unless otherwise specifically stated, that it may include other components, not exclude them. Furthermore, terms such as "...part," "...device," and "module" used in the specification refer to a unit that processes at least one function or operation, which can be embodied in hardware, software, or a combination of hardware and software.

[0042] In multiple embodiments, components having the same configuration will be denoted by the same reference numeral and described as representative of one embodiment, while in other embodiments, configurations different from one embodiment will be described.

[0043] Figure 1 is a block diagram of an ultrasonic imaging system according to one embodiment of the present invention.

[0044] As shown in Figure 1, the ultrasonic imaging system 100 according to this embodiment includes a channel unit 10, a correction unit 20, an imaging unit 30, and a reference information providing unit 40.

[0045] The channel unit 10 consists of multiple channels (for example, piezoelectric elements) and is a transceiver that transmits and receives ultrasonic signals.

[0046] The time delay applied to each channel allows the channel unit to transmit plane wave or divergent waveform ultrasonic signals.

[0047] When the ultrasonic signal transmitted by the channel unit propagates within the body, it is reflected from various points in the soft tissue, each with slightly different physical properties, and the reflected ultrasonic signal is received again by the channel unit.

[0048] Generally, in the absence of a barrier such as a skull, multiple channels constituting the channel section receive ultrasonic signals of nearly the same intensity. However, when ultrasound passes through a barrier such as a skull, the signal intensity between channels is not constant due to the non-uniform distribution of the barrier's physical properties, differences in acoustic impedance, and changes in the incident and transmission angles of the transmitted and received ultrasound. This results in attenuation distortion, which reduces the overall brightness of the image.

[0049] Furthermore, due to the non-uniform distribution of physical properties of a barrier such as a skull, the signal reflected from the object is not incident on each channel simultaneously, resulting in aberration distortion where the wavefronts of adjacent channels are coupled in a non-smooth manner.

[0050] In addition, the ultrasonic imaging system 100 according to the present invention corrects the ultrasonic signal received from the channel unit 10 by the correction unit 20 so that the distortion phenomenon described above does not appear in the ultrasonic image.

[0051] Specifically, the correction unit 20 performs attenuation distortion correction and aberration distortion correction before imaging the ultrasonic signal that has been distorted by a barrier such as a skull.

[0052] First, attenuation distortion correction is intended to solve the problem of the inter-channel signal intensity becoming inconsistent as the ultrasonic signal passes through the barrier. The correction unit 20 performs a correction that scales the amplitude of the ultrasonic signal received for each channel so that it becomes uniform.

[0053] In this case, if the amplitude is made uniform based on the signal of the entire time range entering each channel, an accurate image cannot be obtained.

[0054] Therefore, from the total signal entering the channel, the section relating to the region of interest (ROI), or more specifically, the section estimated to be the signal of the object within the region of interest, is defined as the sample section, and the maximum amplitude or average amplitude of the ultrasonic signals received in each channel is scaled to be uniform based on the maximum amplitude or average amplitude of the sample section.

[0055] Information for determining the sample interval is received from the reference information provision unit 40. The correction unit 20 determines the sample interval using the received reference information, then separates the ultrasonic signal corresponding to the sample interval from the ultrasonic signal, and scales the separated ultrasonic signal so that the maximum amplitude or average amplitude is uniform.

[0056] On the other hand, aberration correction is a correction method to solve the problem of different signal arrival times between channels due to the ultrasonic signal passing through a barrier.

[0057] In the absence of an ultrasonic barrier, ultrasonic signals reflected from the target object are received almost simultaneously by multiple channels constituting the channel section. However, when there is an ultrasonic barrier such as a skull, ultrasonic signals reflected from the target object can be received by each channel with a time difference, making it impossible to know precisely when a signal was received that was reflected from the target object.

[0058] The correction unit 20 then determines a sampling time delay set that moves the section for extracting signal intensity for each channel forward or backward so that the wavefronts of adjacent channels and signals are smoothly connected. Based on the determined sampling time delay set, it extracts the signals to be used for imaging for each channel and transmits them to the imaging unit.

[0059] Here, the correction unit 20 can receive the corrected ultrasonic image, which is an image of the ultrasonic signal transmitted to the imaging unit, and can determine whether the corrected ultrasonic image meets a predetermined image quality standard.

[0060] The predetermined image quality criteria include whether to maximize the brightness of the object, minimize the focal size, or generate an ultrasonic image that most closely resembles the shape of a known object. Furthermore, the predetermined image quality criteria also include whether to generate an image similar to an ultrasonic image produced by an undistorted ultrasonic signal.

[0061] If the corrected ultrasound image does not meet a predetermined standard, the correction unit 20 updates the sampling time delay set and repeats the process of transmitting the signal extracted by the updated sampling time delay set to the imaging unit until the corrected ultrasound image meets the predetermined standard, thereby providing an ultrasound image with minimal distortion due to barriers.

[0062] Furthermore, the correction unit 20 can also determine the sampling time delay set using reference information received from the reference information provision unit 40 (for example, a reference ultrasonic signal or reference image for a reference object), but a detailed explanation of this will be given later.

[0063] The imaging unit 30 visualizes the ultrasonic signal as an ultrasonic image.

[0064] The imaging unit 30 can image the ultrasonic signal received by the channel unit 10 without correction, thereby generating an uncorrected initial distortion image. This initial distortion image is provided to the reference information providing unit 40.

[0065] Furthermore, the imaging unit 30 can visualize the ultrasonic signal corrected by the correction unit 20 to generate an ultrasonic image with corrected aberrations and attenuation distortion. This corrected ultrasonic image is provided to the correction unit 20.

[0066] The method for converting ultrasonic signals into ultrasonic images is a technique widely known to most technicians, so a detailed explanation will be omitted.

[0067] The reference information provision unit 40 provides the correction unit 20 with reference information for correcting signals distorted by barriers.

[0068] The reference information provided by the reference information provision unit 40 is used to predict when each ultrasonic signal received on each channel was reflected from the target object.

[0069] For example, reference information could include the ultrasonic velocity at the ultrasonic barrier, the ultrasonic velocity in the section outside the ultrasonic barrier, the thickness of the ultrasonic barrier, the distance to the object, the size of the object, and the distance between objects.

[0070] Here, the ultrasonic velocity is the statistically known average velocity, maximum velocity, minimum velocity, etc., while the thickness, distance, and size are the statistically known average, maximum, and minimum values, or values ​​predicted from the initial distortion image provided by the imaging unit.

[0071] Furthermore, the reference information consists of a reference ultrasonic signal and / or reference image for a reference object whose shape is already known.

[0072] Here, a reference object is an object that is filmed together with the subject being visualized, and whose shape is already known. For example, the pineal gland or surgical wires can serve as reference objects.

[0073] The reference ultrasonic signal provided by the reference information provision unit 40 is an ultrasonic signal acquired against a reference object in the absence of a barrier, and the reference image is a visualization of the reference ultrasonic signal. Hereinafter, the ultrasonic signal against the reference object will be referred to as the reference ultrasonic signal, and the ultrasonic image against the reference object will be referred to as the reference image.

[0074] Figure 2 is a block diagram of an ultrasonic imaging system according to another embodiment of the present invention. Figure 3 is an image illustrating an exemplary position adjustment method using the position adjustment unit in Figure 2.

[0075] First, as shown in Figure 2, the ultrasonic imaging system 100' according to this embodiment includes a channel unit 10, a correction unit 20, an imaging unit 30, a reference information provision unit 40, and a position adjustment unit 50.

[0076] In other words, the ultrasonic imaging system 100' according to this embodiment differs from the ultrasonic imaging system 100 in Figure 1 in that it further includes a position adjustment unit 50, which allows for further correction of scattering distortion.

[0077] Here, scattering distortion refers to the noise generated in the ultrasonic image due to signals scattered and reflected by the barrier.

[0078] More specifically, the ultrasonic signal transmitted from the channel unit 10 may be partially scattered as it passes through the barrier, and may also be multiple reflections from within the barrier. Some of the scattered or reflected signals may coincidentally enter the channel unit at a time similar to that of the signal echoed by the object, which becomes noise that degrades the image quality of the ultrasonic image.

[0079] This type of noise caused by scattering distortion occurs frequently at the suture lines where skull fragments meet, in areas with greater thickness, and in areas with a high concentration of porous tissue.

[0080] In addition, in the ultrasonic imaging system 100' according to this embodiment, if the image quality of the acquired image does not meet a predetermined standard, the position adjustment unit 50 adjusts the angle and / or position of the channel unit 10, as shown in Figure 3, thereby separating the arrival time of the scattered signal from the arrival time of the video signal (time-gating) and removing noise due to scattering distortion.

[0081] As shown in Figure 3, the position adjustment unit 50 can adjust the position or angle of the channel unit 10 in the horizontal, vertical, and various other rotational directions, as indicated by the arrows, to remove noise caused by scattering distortion.

[0082] In other words, when the angle and / or position of the channel is changed, the signals scattered / reflected by the barrier and the signals reflected from the object will move along different paths than before the angle and / or position of the channel was changed, and will no longer be incident on the channel at similar times.

[0083] Therefore, the signal echoed by the object and the signal scattered and reflected by the barrier are separated in time, and noise due to scattering distortion is removed.

[0084] The intensity of the received ultrasonic signal and the degree of wavefront distortion can be quantified as predetermined criteria for changing the angle and / or position of the channel section, or an index that quantifies the image quality, such as the brightness of the imaged object, spatial resolution, or reference resolution, can be used. The position adjustment unit 50 adjusts the angle and / or position of the channel section 10 until the image quality meets the predetermined criteria, thereby enabling the ultrasonic imaging system 100' according to this embodiment to provide a clear ultrasonic image with noise due to scattering distortion removed.

[0085] The ultrasound imaging method will be explained below with reference to Figures 4 to 6.

[0086] Figure 4 is a sequence diagram of an ultrasonic imaging method using an ultrasonic imaging system according to one embodiment of the present invention.

[0087] As shown in Figure 4, the ultrasonic imaging method according to this embodiment includes an ultrasonic signal transmission step (S10), an ultrasonic signal reception step (S20), a reference information provision step (S30), an attenuation distortion correction step (S40), an aberration distortion correction step (S50), and an optimized image output step (S60).

[0088] The ultrasonic signal transmission step (S10) is a step in which the channel unit 10 transmits an ultrasonic signal toward the target object. Here, the channel unit can transmit a plane wave or divergent waveform ultrasonic signal by applying a time delay to the multiple channels that make up the channel unit.

[0089] The ultrasonic signal reception step (S20) is a step in which the ultrasonic signal transmitted from the channel unit is scattered, reflected, etc., and then re-entered into the channel unit.

[0090] The received ultrasonic signal is a signal containing noise due to attenuation distortion, aberration distortion, and scattering distortion. In the case of the ultrasonic imaging system according to the embodiment shown in Figure 2, the received ultrasonic signal is also a signal from which noise due to scattering distortion has been removed by position adjustment by the position adjustment unit 50.

[0091] The reference information provision step (S30) is a step in which the correction unit 20 provides reference information necessary for attenuation distortion correction and / or aberration distortion correction.

[0092] Reference information is used to predict which of the ultrasonic signals received on each channel was reflected from the target object.

[0093] For example, reference information includes the maximum ultrasonic velocity, minimum ultrasonic velocity, and average ultrasonic velocity at the ultrasonic barrier; the maximum ultrasonic velocity, minimum ultrasonic velocity, and average ultrasonic velocity in sections outside the ultrasonic barrier; the maximum, minimum, and average thickness of the ultrasonic barrier; the distance to the target object; the size of the target object; and the distance between targets.

[0094] The attenuation distortion correction step (S40) is a step that corrects attenuation distortion by equalizing the amplitude of the ultrasonic signals received for each channel.

[0095] On the other hand, Figure 5 is a sequence diagram showing the attenuation distortion correction step in Figure 4. As shown in Figure 5, the attenuation distortion correction step (S40) includes a sample interval determination step (S41), a signal separation step (S42), and an amplitude scaling step (S43).

[0096] Specifically, the correction unit 20 uses the reference information provided by the reference information provision unit 40 to determine the sample interval, which is the time range in which the ultrasonic signal reflected from the target object is incident on the channel unit 10 (S41).

[0097] Subsequently, the signal for the sample interval is separated from the ultrasonic signals received in each channel (S42). For example, if the sample interval is determined to be 100-170 μs (when the ultrasonic frequency is 3 MHz and the target object is approximately 75 mm away from the probe), the ultrasonic signals received in each channel during that time are separated.

[0098] Subsequently, the amplitudes of the separated ultrasonic signals are made uniform (S43).

[0099] For example, the maximum or average amplitude of the ultrasonic signal received by each channel in the sample interval is checked, and the signal is scaled so that the maximum or average amplitude of the ultrasonic signal received by each channel in the sample interval remains constant.

[0100] In this way, by making the amplitude of the sample interval uniform, the problem of the inter-channel signal intensity becoming inconsistent as the ultrasonic signal passes through the ultrasonic barrier can be resolved.

[0101] Next, the aberration distortion correction step (S50) is a step that corrects distortion caused by the difference in signal arrival times between channels due to the ultrasonic signal passing through the ultrasonic barrier, by setting different signal extraction intervals for each channel so that the wavefronts of adjacent channels and signals are smoothly coupled.

[0102] On the other hand, Figure 6 is a sequence diagram showing the aberration correction step in Figure 4. As shown in Figure 6, the aberration correction step (S50) includes a sampling time delay (STD) set setting step (S51) and an optimized STD set selection step (S52).

[0103] In the sampling time delay set setting step (S51), the correction unit 20 can set multiple STD sets within a certain interval (for example, several wavelengths such as 0 to 2 wavelengths) based on an initial STD set that extracts signals estimated to be reflected from the target object. Here, one STD set contains STDs to be applied to each channel (if there are N channels, one STD set contains N STDs), and if there are multiple target objects within the ROI, or if the ROI is segmented, an STD set can be set for each target object or for each segmented ROI.

[0104] Specifically, the correction unit 20 can determine the time when the signal reflected from the target object is received, using, for example, the reference information provided by the reference information provision unit 40 (e.g., the maximum ultrasonic speed, minimum ultrasonic speed, and average ultrasonic speed at the ultrasonic barrier, the maximum ultrasonic speed, minimum ultrasonic speed, and average ultrasonic speed in sections other than the ultrasonic barrier, the maximum thickness, minimum thickness, and average thickness of the ultrasonic barrier, the distance to the target object, the size of the target object, the distance between target objects, etc.), and then use the determined time to determine the initial STD set.

[0105] Furthermore, the correction unit 20 can determine the initial STD set so that the signal with the strongest signal intensity is extracted from the received signals (uncorrected signals or signals corrected for attenuation distortion) for each channel. For example, in the received ultrasonic signal shown in Figure 9a, the signal indicated by the black dot can be extracted, and in the ultrasonic image shown in Figure 9b, the signal that forms the peak can be extracted.

[0106] Subsequently, a certain interval from the initial STD set is designated as the sampling time delay selection interval, and multiple STD sets can be set within this interval. The STD selection interval is a smaller interval than the sample interval used to match the signal amplitude in the aforementioned attenuation distortion. For example, the sample interval selected for amplitude correction of attenuation distortion is a signal interval in which 1300 to 2000 signal samples are received. However, the STD selection interval for aberration correction is an interval corresponding to the position of a specific target object, exhibiting a curved shape for each channel, and meaning an interval within a few wavelengths (a signal interval in which several to several dozen signal samples are received).

[0107] The optimized STD set selection step (S52) is a step in which an STD set is selected from among several STD sets to produce video with the optimal image quality.

[0108] The correction unit 20 can select an optimized STD set using a heuristic algorithm such as a genetic algorithm or a particle swarm optimization algorithm, sensitivity, or a gradient-based algorithm. In this case, the optimized STD set is an STD set that smoothly connects adjacent channels and the wavefront of the signal, and the image with optimal image quality is one that maximizes the brightness of the object, minimizes the size of the focal point (e.g., the size from the center of a pixel with a pressure reference of -6dB or higher), or resembles the shape of a known object (e.g., the shape of a -6dB pixel).

[0109] As shown in Figure 6, the sampling time delay (STD) set setting step (S51) is followed by the optimized STD set selection step (S52). However, as indicated by the dotted arrow, in order to select the STD set with the optimal image quality, the process can return to the sampling time delay set setting step based on the image quality evaluation results, and in this case, a new STD set can be selected that reflects the image quality evaluation results.

[0110] Referring again to Figure 4, after the correction steps described above, in the optimized video output step (S60), an ultrasonic image from which noise due to aberration distortion and attenuation distortion has been removed is output.

[0111] Although Figure 4 shows that aberration distortion is corrected after damping distortion correction, this does not rule out the possibility that damping distortion correction is performed after aberration distortion correction.

[0112] Figure 7 shows an ultrasonic imaging method using an ultrasonic imaging system according to another embodiment of the present invention.

[0113] As shown in Figure 7, the ultrasonic imaging method according to this embodiment includes an ultrasonic signal transmission step (S10), an ultrasonic signal reception step (S20), an initial distortion image generation step (S70), a reference information provision step (S30'), an attenuation distortion correction step (S40'), an aberration distortion correction step (S50'), and an optimized image output step (S60).

[0114] Unlike the ultrasonic imaging method shown in Figure 4, the ultrasonic imaging method according to this embodiment further includes an initial distortion image generation step (S70).

[0115] In the following, when describing the ultrasonic imaging method according to this embodiment, the steps that are the same as the ultrasonic imaging method in Figure 4 will be described as previously explained, and the ultrasonic imaging method according to this embodiment will be described focusing on the parts that differ from the ultrasonic imaging method according to the previously described embodiment, by further including the initial distortion image generation step (S70).

[0116] The initial distortion image generation step (S70) is a step in which the ultrasonic signal received by the channel unit, that is, the ultrasonic signal that has not been corrected for distortion caused by the barrier, is visualized as an ultrasonic image. In other words, the initial distortion image is an ultrasonic image generated from an ultrasonic signal that contains noise caused by distortion generated by the barrier.

[0117] After generating an initial distorted image, the imaging unit 30 can provide the reference information providing unit 40 and / or the correction unit 20 with the initial distorted image and / or an uncorrected ultrasonic signal for distortion correction.

[0118] In the reference information provision step (S30), the reference information provision unit 40 can provide, as described above, the maximum ultrasonic speed, minimum ultrasonic speed, and average ultrasonic speed at the barrier, the maximum ultrasonic speed, minimum ultrasonic speed, and average ultrasonic speed in the section other than the barrier, the maximum thickness of the barrier, the minimum thickness of the barrier, the distance to the object, the size of the object, and the distance between objects.

[0119] Furthermore, the reference information provision unit 40 identifies the reference object from the initial distorted image and provides the reference ultrasonic signal and / or reference ultrasonic image to the correction unit 20. In this case, the reference ultrasonic signal and / or reference ultrasonic image is information that has been pre-stored in the reference information provision unit.

[0120] The correction unit 20, provided with a reference ultrasonic signal and / or reference ultrasonic image, can use the reference ultrasonic signal and / or reference ultrasonic image in the attenuation distortion correction step (S40') to determine a more accurate sample interval for attenuation distortion correction.

[0121] In other words, the correction unit 20 can predict the time difference due to the barrier by comparing the section in the ultrasonic signal received by the channel unit in which a signal indicating the reference object is received with the section in the reference ultrasonic signal in which a signal indicating the reference object is received. If we further consider the distance difference (or arrival time difference) between the reference object and the target object, we can more accurately determine the sample section, which is the time range in which the ultrasonic signal reflected from the target object is incident on the channel unit 10.

[0122] Furthermore, by comparing the intensity of the signal indicating the reference object with the intensity of the reference ultrasonic signal in the ultrasonic signal received in the channel section, it is possible to predict changes in signal intensity due to the barrier. In addition, in the attenuation distortion correction step (S40'), by scaling the signal amplitude of the sample section to a constant value, it is possible to further correct for changes in the overall decrease or increase in signal intensity due to the barrier.

[0123] Next, in the aberration distortion correction step (S50'), the correction unit 20 can determine a more optimized STD using the reference ultrasonic signal and / or reference ultrasonic image.

[0124] Specifically, the correction unit 20 can predict the time difference due to the barrier by comparing the section in the ultrasonic signal received by the channel unit in which a signal indicating the reference object is received with the section in the reference ultrasonic signal in which a signal indicating the reference object is received. The time difference profile obtained by interpolating such a time difference or channel-specific time difference can be determined as the M initial sampling time delay (STD) set.

[0125] Subsequently, the STD can be optimized by comparing the ultrasound image generated using the initial STD set with the reference image and updating the STD set to minimize the standard deviation or variance of the corresponding pixel intensity in the two images.

[0126] Specifically, in order to update and optimize the STD set, the correction unit 20 sets a certain interval within a few wavelengths from the initial STD set as the STD selection interval, sets multiple STD sets in this interval, and then selects the STD set that generates the image with optimal image quality as the optimized STD set. Here, the image with optimal image quality is the image in which the standard deviation or variance of pixel intensity is minimized compared to the reference image. Here, the pixel intensity is the brightness value, but is not limited to this.

[0127] The ultrasound imaging system and ultrasound imaging method have been described above.

[0128] As can be seen from Figures 8a and 8b, which show the ultrasound signal and ultrasound image measured on a vascular model tube (2 mm in diameter, Teflon) without an ultrasound barrier, and Figures 9a and 9b, which show the ultrasound signal and ultrasound image measured on the same vascular model tube with an ultrasound barrier such as a skull, when an ultrasound barrier is present, a lot of signal distortion occurs in the ultrasound signal, and as a result the ultrasound image differs greatly from the actual state of the target body (signal intensity decreases by approximately 170 times, horizontal tube size error of approximately 400%, and horizontal tube position error of approximately 50%).

[0129] Herein, the ultrasonic imaging system and ultrasonic imaging method according to the embodiment of the present invention can correct distortion caused by the ultrasonic barrier by attenuation distortion correction, which scales the amplitude of the sample section to a constant value; aberration distortion correction, which adjusts the signal extraction section with STD optimized for each channel; and scattering distortion correction, which moves the position of the channel section. As shown in Figures 10a and 10b, the ultrasonic image using the corrected ultrasonic signal can be corrected to closely resemble the actual state of the object (signal intensity is improved fourfold compared to before correction, tube size error is reduced from 400% to 37%, and tube position error is reduced from 50% to 6.2%).

[0130] In particular, when using a reference ultrasonic signal and a reference ultrasonic image, the ultrasonic imaging system and ultrasonic imaging method according to the present invention can obtain an accurate ultrasonic image of a target object even if the ultrasonic signal transmission step and ultrasonic signal reception step are performed only once for the target object.

[0131] However, the ultrasonic imaging method according to the embodiment of the present invention is not limited to performing the ultrasonic signal transmission step (S10) and the ultrasonic signal reception step (S20) once, but can be performed two or more times.

[0132] In other words, by changing the angle at which the channel unit 10 is steered, ultrasonic signals are acquired at various angles, and these signals are used to acquire ultrasonic images of the target object, thereby improving spatial and comparative resolution.

[0133] Here, by using the optimized STD set for the i-th ultrasonic beam with irradiation angle θ as the initial STD set for the (i+1)th ultrasonic beam with irradiation angle θ+dθ, the optimized STD set can be derived more quickly.

[0134] Furthermore, if the regions of the i-th ultrasonic beam and the (i+1)-th ultrasonic beam overlap, and the ultrasonic propagation directions in a particular channel K are close, even if their ROIs (or ultrasonic irradiation angles) are different, they can share the STD (Standard Time Diagram) and derive the optimal STD value more quickly.

[0135] Figure 11 is a sequence diagram showing an ultrasonic imaging method according to yet another embodiment of the present invention. Specifically, Figure 11 shows a method for restoring an image that controls the position of the ultrasonic probe, improves the signal-to-noise ratio of the target object, and facilitates subsequent attenuation and aberration distortion correction. The target signal, which is recognized as noise in relation to the signal of the target object, can become a serious electrical noise signal due to the scattering signals, reverberation signals, and attenuation of the porous tissue of the skull as described above.

[0136] As shown in Figure 11, the ultrasonic imaging method (S100) according to this embodiment includes the steps of transmitting an ultrasonic signal (S110), receiving an ultrasonic signal (S120), converting the received analog signal into a digital signal, and beamforming (S130) combining the received channel-specific signals for the transmitted ultrasonic signals to correspond to the pixels of each image, an intermediate processing step (S140) for efficient imaging by extracting the phase and envelope of the signal or reducing the number of signal samples for future acquisition of B-mode images or Doppler signals, outputting and updating the image in the first order (S150), calculating the signal-to-noise ratio of the target object, and if the signal-to-noise ratio conditions are met (step S160), performing the aforementioned attenuation or aberration correction (S170), and if the signal-to-noise ratio conditions are not met (S160), changing the probe position to find an acoustic window that reduces the aforementioned noise (S190).

[0137] The steps of converting to a digital signal as mentioned in Figure 11, the beamforming step (S130) of the received signal for the transmitted ultrasound, and the intermediate processing step (S140) are general imaging methods for ultrasound diagnostic equipment and are basically included in the imaging process of the embodiment described above. Furthermore, in the case of the object and image in this embodiment, general diagnostic modes such as B-mode or Doppler mode are included.

[0138] Furthermore, in this embodiment, transmitting ultrasound generally refers to irradiating ultrasound with various ultrasonic irradiation directions, convergence depths, or scan lines, and is a known method for generating a compound image. Although not shown in the figures, as mentioned above, it can also be applied to a process in which multiple different ultrasounds are transmitted toward a barrier, and attenuation and aberration distortion are corrected for each received signal depending on the transmission mode.

[0139] Figure 12 is a sequence diagram showing an ultrasonic imaging method according to yet another embodiment of the present invention. Specifically, Figure 12 shows a method for applying the time delay set found by the aberration correction method described above to the beamforming signal of the ultrasonic transmission channel.

[0140] Specifically, the imaging method (S101) in this embodiment consists of the steps of: transmitting an ultrasonic signal toward an ultrasonic barrier (S110); receiving an ultrasonic signal distorted by the ultrasonic barrier (S120); constructing an initial image based on the received signal (this includes digital signal conversion and received signal beamforming (S130), and an intermediate signal processing process (S140)); correcting attenuation distortion or aberration distortion caused by the ultrasonic barrier (S151); outputting the image (S161); calculating the resolution conditions of the target object based on the output image (S171); and, if the resolution conditions are not met (S170), applying an optimal time delay set for aberration correction or a channel-weighted signal size set for attenuation correction to the signal transmission channel (S181), and irradiating with newly beamformed ultrasonic waves.

[0141] Here, by applying a time delay set or a channel-weighted signal size to the beamforming of the transmitted ultrasound, it is possible to physically correct the aberration or attenuation distortion of the target object, thereby shortening and simplifying the aforementioned post-processing attenuation and aberration distortion correction process.

[0142] The aforementioned resolution conditions include the brightness of the image of the target object, the focal size, the phase or amplitude deviation from the reference image, the phase or amplitude deviation from the reference channel signal, and the time difference or amplitude deviation from the reference time delay set.

[0143] Furthermore, even if the resolution requirements for the target object are met, the feedback loop continues, which is generally a process in which the ultrasound image is updated at a high frame rate, allowing for better observation of the object's movement.

[0144] Furthermore, although not shown in the figures, the ultrasonic probe position control method and the method of applying the found time delay set to beamforming of transmitted ultrasound, as shown in Figures 11 and 12, can be carried out in combination with each other, either with one method completed first and the other performed, or with both methods being performed together each time in a feedback loop that is repeated in a series of sequences.

[0145] According to the present invention as described above, in a signal distorted by an ultrasonic barrier, the position of the channel portion is moved so that scattering distortion is included as little as possible, the amplitude of the signal in which attenuation distortion occurs is scaled, and an appropriate sampling time delay is applied to each channel of the signal in which aberration distortion occurs, thereby enabling high-resolution imaging of an object beyond the ultrasonic barrier.

[0146] Furthermore, the present invention is not only applicable to medical ultrasound imaging devices that transmit and receive ultrasound waves into barrier tissues with non-uniform physical properties and shapes, such as bone tissue, soft tissue, and gas, which induce aberrations, attenuations, and scattering distortions of ultrasound, but can also be widely used in various non-destructive testing industrial fields that use ultrasound to visualize barriers (composite materials, thermal insulation materials, rust and sludge in pipes, etc.) that induce aberrations, attenuations, and scattering distortions of ultrasound, including solids (metals, ceramics, plastics, etc.) or fluid substances of multiple compositions.

[0147] The ultrasonic imaging system and method according to the present invention have been described above with reference to specific embodiments. However, it should be understood that the present invention is not limited to these specific embodiments, and that various changes and modifications are possible without departing from the spirit and scope of the invention claimed in the claims.

Claims

1. A channel section including multiple channels for transmitting and receiving ultrasound, The channel unit includes a correction unit that corrects distortion caused by an ultrasonic barrier using the ultrasonic signal received in the channel unit, An imaging unit that visualizes ultrasonic signals as ultrasonic images, Includes a reference information providing unit that provides the correction unit with reference information necessary for correction, The ultrasonic imaging system is characterized in that the correction unit determines a sample interval using the reference information and corrects attenuation distortion and aberration distortion caused by the ultrasonic barrier based on the signal of the sample interval.

2. The correction unit, Using the aforementioned reference information, a sample interval is determined in which ultrasonic signals reflected from the target object can be received. When correcting the attenuation distortion, the signal of the sample section is separated from the ultrasonic signal received in the channel, and then the amplitude of the separated ultrasonic signal is made uniform to correct the attenuation distortion caused by the ultrasonic barrier. The ultrasonic imaging system according to claim 1, characterized in that, when correcting the aberration distortion, a sampling time delay is applied to each channel to extract the signal to be imaged, and the aberration distortion caused by the ultrasonic barrier is corrected.

3. The ultrasonic imaging system according to claim 2, characterized in that the correction unit determines an initial sampling time delay set in which it is predicted that an ultrasonic signal reflected from the target object has been received, sets a plurality of sampling time delay sets within a certain interval range from the determined initial sampling time delay set, selects a sampling time delay set that can generate an image with a preset optimal image quality as the optimized sampling time delay set, and extracts the signal to be imaged using the selected optimized sampling time delay set.

4. The ultrasonic imaging system according to claim 3, characterized in that the correction unit determines the initial sampling time delay set so that the signal with the strongest signal intensity is extracted from the ultrasonic signals received by the channel unit.

5. The ultrasonic imaging system according to any one of claims 1 to 4, characterized in that the reference information includes one or more of the following: ultrasonic velocity in the ultrasonic barrier, ultrasonic velocity in the section other than the ultrasonic barrier, thickness of the ultrasonic barrier, distance to the object, size of the object, and distance between objects.

6. The ultrasonic imaging system according to claim 3, wherein the reference information includes a reference ultrasonic signal for a reference body whose shape is already known and which has been photographed together with the target body, or a reference image obtained by imaging the reference ultrasonic signal, and the reference ultrasonic signal or reference image is acquired in the absence of an ultrasonic barrier.

7. The ultrasonic imaging system according to claim 6, characterized in that the correction unit determines the sample interval by considering the time difference between the interval in the received ultrasonic signal in which a signal indicating the reference object is received and the interval in the reference ultrasonic signal in which a signal indicating the reference object is received, and the distance difference between the reference object and the target object.

8. The ultrasonic imaging system according to claim 7, characterized in that the correction unit selects the optimized sampling time delay set from among a plurality of sampling time delay sets based on image quality, and the optimized sampling time delay set based on image quality is a sampling time delay set that can either maximize the brightness of the target object, minimize the size of the focal point, or generate an ultrasonic image with a shape that is most similar to the shape of a known target object.

9. The ultrasonic imaging system according to claim 6, characterized in that the correction unit selects, from among a plurality of sampling time delay sets, a sampling time delay set that minimizes the standard deviation or variance of intensity between the ultrasonic image obtained by the corrected ultrasonic signal and the corresponding reference image pixels, as the optimized sampling time delay set.

10. The steps include transmitting an ultrasonic signal toward an ultrasonic barrier, The steps include receiving an ultrasonic signal that has been distorted by the aforementioned ultrasonic barrier, A step of providing the reference information necessary for correction, Using the aforementioned reference information, a sample section is determined in which an ultrasonic signal reflected from the target object can be received, and based on the signal in the sample section, the attenuation distortion due to the ultrasonic barrier is corrected. A step of correcting aberration distortion caused by the ultrasonic barrier based on the signal of the sample section, An ultrasonic imaging method characterized by comprising the step of imaging a corrected ultrasonic signal with an ultrasonic image.

11. In the step of correcting the attenuation distortion, after separating the signal of the sample section from the received ultrasonic signal, the amplitude of the separated ultrasonic signal is made uniform to correct the attenuation distortion caused by the ultrasonic barrier. The ultrasonic imaging method according to claim 10, characterized in that, in the step of correcting the aberration distortion, a sampling time delay is applied to each channel to extract the signal to be imaged, and the aberration distortion caused by the ultrasonic barrier is corrected.

12. The step of correcting the aberration distortion is: The steps include determining an initial sampling time delay set that is predicted to occur when an ultrasonic signal reflected from the object is received, The steps include setting multiple sampling time delay sets within a certain interval range from the initial sampling time delay set, The steps include selecting an optimized sampling time delay set, which is a sampling time delay set capable of generating video with a pre-set optimal image quality, and The ultrasonic imaging method according to claim 11, further comprising the step of extracting the signal to be imaged using a selected optimized sampling time delay set.

13. The ultrasonic imaging method according to claim 12, characterized in that the step of determining the initial sampling time delay set is determined so that the signal with the strongest signal intensity is extracted.

14. The ultrasonic imaging method according to any one of claims 10 to 13, characterized in that the reference information includes one or more of the following: ultrasonic velocity at the ultrasonic barrier, ultrasonic velocity in the section other than the ultrasonic barrier, thickness of the ultrasonic barrier, distance to the object, size of the object, and distance between objects.

15. The ultrasonic imaging method according to claim 12, wherein the step of providing the reference information involves detecting a reference body whose shape is already known and which has been photographed together with the target body, and providing a reference ultrasonic signal for the target body acquired without an ultrasonic barrier, or a reference image obtained by imaging the reference ultrasonic signal, as reference material.

16. The ultrasonic imaging method according to claim 15, characterized in that an optimized sampling time delay set is selected, which minimizes the standard deviation or variance of the intensity between the ultrasonic image obtained by the corrected ultrasonic signal and the pixels of the corresponding reference image.

17. The ultrasonic imaging method according to claim 12, characterized in that the optimized sampling time delay set is a sampling time delay set that maximizes the brightness of the target object, minimizes the size of the focal point, or generates an ultrasonic image with a shape most similar to that of a known target object.

18. The steps include transmitting an ultrasonic signal toward an ultrasonic barrier, The steps include receiving an ultrasonic signal that has been distorted by the aforementioned ultrasonic barrier, The steps include: calculating the signal-to-noise ratio of the target object, The steps include changing the probe position to reduce the signal-to-noise ratio, A step of correcting attenuation or aberration distortion due to the ultrasonic barrier based on the signal of the sample section, An ultrasonic imaging method characterized by comprising the step of converting a corrected ultrasonic signal into an ultrasonic image.

19. The steps include transmitting an ultrasonic signal toward an ultrasonic barrier, The steps include receiving an ultrasonic signal that has been distorted by the aforementioned ultrasonic barrier, A step of correcting attenuation or aberration distortion due to the ultrasonic barrier based on the signal of the sample section, The steps include: calculating the resolution requirements for the target object, The steps include applying an optimal time delay set for aberration correction to the signal transmission channel and irradiating it with newly beamformed ultrasound, An ultrasonic imaging method characterized by comprising the step of converting a corrected ultrasonic signal into an ultrasonic image.

20. The steps include: calculating the signal-to-noise ratio of the object; The ultrasonic imaging method according to claim 19, further comprising the step of changing the probe position to reduce the signal-to-noise ratio.

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